Feeling all warm and fuzzy? Chalk it up to oxytocin, the touchy-feely hormone that enables mothers to bond with their babies (thus the nickname the “cuddle chemical”). Oxytocin fluctuates throughout our lives—during and after childbirth, as well as when you’re sexually aroused or reach the big O. But this feel-good chemical may have a surprising dark side, according to research published in the August issue of the journal Current Directions in Psychological Science.

Rather than oxytocin making them feel like they were in the “trust tree” singing “Kumbaya,” study subjects given the chemical before playing a game of chance exhibited more gloating and envy of their opponents. According to the study co-author Andrew Kemp, Ph.D., of the University of Sydney, the new theory behind oxytocin is that it’s not necessarily about booting positive social emotions, but rather the chemical may increase the so-called approach-related emotions. These are feelings that have to do with wanting something, which can skew positive—into generosity and altruism—or negative—into envy and gloating.